The first command assigns the alias h to the
history command. The next command assigns the alias
rev to the command h | tail -10.
This takes the output from the alias h ( the
history command) and pipes it through the
tail command to list the ten most recent commands in the
command history.

To pass command arguments to the alias:

alias print 'lpr \!^ -Pps5'

To print a file to the printer ps5 the user enters a
command such as:

print memo.txt

The notation !^ causes the first argument to the command
alias print to be inserted in the command at this point.
The command that is carried out is: